How can I rig multiple identical legs efficiently?
Sadly the array modifier is not able to do this like it would be with the mirror modifier (copy Vertex Groups automatic) but I would make one Leg perfect (I would prefer the one on the X Axis) with a perfect Armature just for one leg and then duplicate and rotate the rig and the leg (together) to make the full robot. Try to join the armature and meshes together but I dont know if that works.
For the pivot point Problem move the start point of the bone to control the "center point".